The present invention relates to a method for manufacturing a pneumatic tire provided on the radially inside of the tread portion with a noise damper, more particularly to a technique for molding the noise damper during vulcanizing the tire.
Pneumatic tires provided on the radially inside of the tread portion with a noise damper made of foamed material has been proposed in order to damp resonance of air in the annular tire cavity. Thus, tire noise during running can be reduced.
In the laid-open Japanese patent application No. 2003-285607, a method for manufacturing a pneumatic tire of this kind is disclosed, wherein an expandable material for the noise damper is applied to the inner surface of an unvulcanized tire; the unvulcanized tire is put in a mold; an inflatable bladder is set in the tire hollow; and the bladder is inflated during heating the tire to thereby mold and vulcanize the tire and at the same time expand the expandable damper material.
In this method, the inflated bladder presses the expandable damper material. Further, irrespective of partially or wholly, the tire is pressed onto the inside of the mold indirectly through the expandable material. Thus, it is very difficult to achieve dimensionally accurate, sufficient foaming of the expandable material and accurate molding of the tire at the same time.